1. Field of the Invention
The invention relates to a lift of the type used for inclined lift applications, such as chair lifts, in which a frame or chassis member, supported by guide rollers, is moveable along a track having a pair of parallel, tubular guide rails. The present lift can be used either in inclined or vertical lift (i.e., elevator) applications.
2. Description of Related Art
In known inclined lifts, a pair of spaced guide rails are used to guide the rollers. The lift is driven, however, with a separate driving mechanism.
In one known apparatus, an endless cable runs inside the hollow guide rails and is connected to the moveable frame through a slot in the upper guide rail. In another apparatus, the frame is moved via toothed racks that extend parallel to the rails and on which a gear runs.
In German patent No. DE-PS 29 46 780, the frame is driven by a worm that engages a worm gear, in which the gear teeth are laid out on a plurality of plates.
All known lift devices of this general type have the disadvantage that both their production and their assembly are expensive.
European patent application No. 0 088 061 discloses a hanging conveyor, in which a chair lift hangs off a single track tube. A drive device, in frictional contact with the track, is used to move the chair lift along the track. This type of design has the critical disadvantage that it has no secure guide for the suspended load. Therefore, in most cases these designs are not permissible as lifts for people, in particular as lifts for the handicapped.